Diet of nestling red-cockaded woodpeckers at three locations
We conducted a 2-yr study of the nestling diet of red-cockaded woodpeckers (Picoides borealis) at three locations to determine how it varied among sites. We photographed 5939 nest visits by adult woodpeckers delivering food items for nestlings. In 1994, we located cameras near three nest cavities on the Lower Coastal Plain of South Carolina and near two cavities at the Savannah River Site, which is on the Upper Coastal Plain. In 1995, cameras were installed on the Savannah River Site and in the Piedmont National Wildlife Refuge, GA. The cameras recorded adults bringing 33 different types of food to nestlings. Wood roaches (Blattoidea: Blattellidae, Parcoblatta spp.) were the most common food, composing 50 percent of the diet overall. They were also the most common prey at each location and for all but one of the woodpecker groups studied. Wood roaches were recorded in 26 percent of the visits photographed on the Lower Coastal Plain and 62 percent of the nest visits on the Upper Coastal Plain in 1994. In 1995, wood roaches were recorded in 57 percent and 50 percent of the visits on the Upper Coastal Plain and Piedmont, respectively. Woodpeckers on the Lower Coastal Plain used blueberries (Vaccinum sp.) and sawfly larvae (Hymenoptera: Diprionidae, Neodiprion sp.), two dietary items not commonly used at the other locations. Adults at two locations providing [provided] snail shells to nestlings, possibly as an additional source of calcium. Morista's index of diet overlap (C) ranged from 0.94 to 0.99 for breeding males and females in the same group, from 0.63 to 0.99 among groups at the same location, and from 0.68 to 0.96 among locations. Because diet overlap of red-cockaded woodpecker nestlings at different geographical locations was within the range that occurred among groups at the same location, we conclude that nestling diets are similar across the geographical area studied, and that it varies little from year to year.